Known in the art is U.S. Pat. No. 4,211,930, granted on Jul. 8, 1980 to Werner H. FENGLER. This patent describes an engine-driven-alternator individual-wheel-motorized electric propulsion system for a four-wheel motor vehicle provided with a steering mechanism. The system comprises an engine-driven two-phase alternator having a two-phase alternator output, a plurality of electric stepping motors adapted to be drivingly connected one to each vehicle wheel, a storage battery, a pulse-responsive electric power system including a plurality of gate-controlled rectifiers having power current input means and also having power current output means, and a stepping motor control circuit interposed between and connecting said alternator output to said motor inputs and including switching means connected to the gates of said gate-controlled rectifiers and responsive to the reception of positive or negative pulses for selectively energizing first and second windings of the stator pole pieces separately and simultaneously and thereby effecting step-by-step rotation of the rotors. As can be seen, the engine-driven two-phase alternator provides most of the energy to supply the stepping motors. The battery is used only when additional energy is needed. One drawback is that most of the energy is supplied by the alternator which requires consumption of fuel.
Also known in the art is U.S. Pat. No. 4,951,769, granted on Aug. 28, 1990 to Hideo KAWAMURA. The motor vehicle drive system described in this patent uses only the battery for supplying the vehicle accessories.
Also known in the art is U.S. Pat. No. 4,928,227 et al, granted on May 22, 1990, to Joseph C. BURBA et al, in which there is described a method for controlling a motor vehicle powertrain where the vehicle is powered either by a battery or by a gas powered motor generator.
Also known in the art is U.S. Pat. No. 3,792,742, granted on Feb. 19, 1974, to Charles J. MAGER, in which there is described an electric motor powered vehicle operating essentially on batteries.
Also known in the art is U.S. Pat. No. 3,421,596, granted on Jan. 14, 1969 to H. W. CHRISTENSON et al. In this patent, there is described a transmission for a vehicle where each wheel of the vehicle is driven by an electric motor. The vehicle has an internal combustion engine as its prime mover.
Also known in the art is U.S. Pat. No. 4,495,451, granted on Jan. 22, 1985 to Maxwell K. BARNARD. In this patent, there is described an internal energy interchange system for interchanging energy between driving wheels and flywheels. The system is essentially powered by an internal combustion engine.
Also known in the art is U.S. Pat. No. 4,913,258, granted on Apr. 3, 1990, to Hiroshi SAKURAI. In this patent, there is described an electric vehicle which is essentially powered by electrical energy.
None of the above patents provides a motor vehicle driving system comprising a powered battery and a combustion motor electric power supply where the powered energy is primarily provided by the power battery to keep to a minimum the consumption of fuel.
It is an object of the present invention to provide a motor vehicle drive system for a motor vehicle where a power supply bus is primarily supplied by a battery, and where a combustion motor electric power supply provides auxiliary energy when predetermined conditions are met.
It is another object of the present invention to provide a motor vehicle drive system primarily powered by a battery which is smaller than the one used in the prior art.